The present invention relates to an apparatus for heat transfer. More particularly, this invention relates to an apparatus for heat transfer of the type which precludes possible reverse flow of heat energy even when the temperature on the input side falls below that on the output side.
The heat pipe which has heretofore been used as one form of heat transfer means will be explained. The heat pipe is a device employed for effecting the transfer of heat by utilizing capillary action in conjunction with the difference of pressure created inside the pipe. On the input side (heat-absorption portion) of the heat pipe, the heat medium absorbs heat and is consequently vaporized and the vaporized heat medium is moved in the direction of the output side (heat-radiation portion) by virtue of the difference of pressure. On the output side, the heat medium liberates heat and is consequently liquefied. The liquefied heat medium is now made to flow through the wick inside the heat pipe back to the input side by virtue of capillary action coupled with the suction resulting from the vaporization of the heat medium on the input side. Because of the difference of pressure resulting from the difference of temperature between the input side and the output side, the heat medium which is vaporized on the input side is made to move from the input side to the output side. When the heat pipe in which the heat medium is moved by virtue of the difference of pressure as described above is used in a heat-absorption device such as a solar energy absorption device which experiences abrupt changes of input energy, however, there is entailed a possibility that reverse flow of heat medium will occur when the heat energy on the input side of the heat pipe decreases sharply and the temperature on the input side falls below that on the output side.
An object of the present invention is to provide an apparatus for heat transfer of the type which precludes otherwise possible reverse flow of heat energy even when the temperature on the input side falls below that on the output side.